Stem and bit locking device



` 1,390,931, 'Patenfedsepn 13,1921.`

.JIJ/1nl PS/ramberger INVENTUR. n

ATTORNEY.

PATENT OFFICE.

JOHN P. SHAMBERGER, 0F BALTIMORE, MARYLAND.

STEM ANDV BIT LOCKING DEVICE.

Specification of Letters Patent.

Patented Sept. 13, 1921.

Application led October 21, 1919. Serial No. 332,136.

To all whom t may concer-n:

Be it known that I, JoHN P, SHAMBERGER, a citizen of the United States, residing at Baltimore, in the county of Baltimore and State of Maryland, have invented new and useful Improvements in Stem and Bit Locking Devices, of which the following isa specification.

The invention relates to well drilling tools and has for an object to provide a lock for use in locking the bit to the stem of a well drilling tool.

Among other features the invention com prehends a lock of simple construction and which is so arranged as to permit of the ready connection of a bit with the stem and the locking thereof to the stem,also providing for the ready unlocking of the bit from the stem and its subsequent removal therefrom so that with the use of the lock to be described, the bit cannot accidentally remove itself from the stem while in use.

In the further disclosure of the invention reference is to be had to the accompanying drawings, constituting a part of this specification, in which similar characters of reference denote corresponding parts in all the views, and in which.

Figure 1 is a fragmentary elevation of a stem and the bit thereof, showing the latter locked to the stem.

Fig. 2 is a similar view with the locking in or bar in unlocked position and the bit 1n the process of removal from the stem.

` Fig. 3 is a vertical longitudinal sectional view taken on the line 3 3 in Fig. 1, and

Fig. 4 is a horizontal sectional view taken substantially on the line 4-4 in Fig. 3.

eferring more particularly to the views, the numeral 10 indicates a stem and the numeral 11, a bit, the latter having a threaded tapered shank 12 for threaded engagement with the stem 10 as shown, the formation of the shank 12 on the bit 11, providing a ledge or surface 13 which abuts against an end 14 of the stem when the bit is applied.

A longitudinal bore or opening 15 is formed in the stem 10 immediately adjacent the periphery 16 thereof, thus providing an intermediate wall 17 and disposed in this `opening 15 is an expansible helical spring 18, the lower end of which abuts against a locking bar or pin 19 arranged to slide in the opening 15. The bit 11 is similarly formed with a bore or opening 20, the bottom 21 of which has a cross groove 22 therein and the outer wall 23 of the opening 20, is formed with a vertical slot 24, the lower end of which at 25 communicates with the cross groove -22 and is in fact a part thereof. The wall 17 is also formed with a longitudinal slot 26 which is adapted to register with the slot 24 when the bit is screwed into the stem and the slot 26 terminates at its upper end in a cross portion 27 the bottom of which is formed with notches 28 defining retaining lugs 29 in the wall 17. A projection or pin 30 is provided onthe locking bar 19 and operates in the slots 24, 26, and the cross portion 27.

Now it will be apparent that when the locking bar 19 is raised against the action of the spring 18 so that the lower part of the locking bar will lie within the opening 15 and above the horizontal plane of the ledge or surface 13, the bit will be in un* locked relation relative to the stem, the locking bar 19 having been slightly rotated when moved upwardly so as to bring the rejection or pin 30 out of the slot 26 and mto one of the cut out portions 28 to rest against and be held by one of the side lugs 29 against the downward action of the spring. The bit can now be readily disengaged from the stem and when at a subseuent time it is desired to secure the bit to tie stem and lock it in vosition so as to prevent accidental remova of the bit when the drilling tool is in use the bit is first threaded into the stem in the usual manner to bring the slots 24, 26, into registration thus also bringing the openings 15, 20, into registration. The projection or lug 3() is now moved out from the cut out portions 28 in which it has been reposing and is brought into alinement with the slot 26 and then released, thereby permitting the spring n 18 to act and force the locking bar downwardly into the opening 2O to the bottom 21 thereof, thus bringing the projection or lug 30 into the slot 24. It will be apparent that the projection or lug 30, because of the engagement of the locking bar 19 with the bottom 21 of the opening 20, will not liein the lowermost portion of the slot 24 so that the lower portion 25 of the slot will be free and open, permitting of the insertion of a nail or other similar implement into the lower portion 25 of the slot and into the groove 22, to engage against the underside of the locking bar 19 so as to permit of raising the same against the action of the spring when it is again desired to unlock the bit relative to the stem.

I preferably dispose the lock described, adjacent the peripheries of the stem and bit s as to obtain the greatest locking action and prevent a shearing of the locking bar when it is in locked position, although if the locking bar is made sufficiently large, this would hardly be possibly, unless an exceptional torsion were exerted on the bit. It will be apparent however that with my form of device no part of the lock comprisy ing thebar, the spring and the projection or lug, extends beyond the peripheries of the stem or bit and no interference with the threaded connection between the stem and bit results in having the lock disposed in the particular manner mentioned.

Although I am aware that ordinarily a bit threaded into the stem of a well drilling tool is partially prevented from disengagement thereof by reason` of the friction between the threads in contact with each other and the friction between the shoulder or end of the stem and the shoulder or flange 18 of the bit, I have found that in actual r use this friction is not always sufficient to v maintain the blt and stem in proper threaded engagement and that the provision of an additional locking element is necessaryand it is for this reason that I have provided the simple and effective lock described and shown herein.

Having described my invention, I claim,-

A lock for the bit and stem of a well from said plunger and movable along the registering slots, the pin being engugable within either of said notches whereby to hold the plunger in retracted position out of engagement with the recess in the bit.

In testimony whereof I aHix mvsignature.

JOHN P. SHAMBERGER. 

